Charting elimination in the pandemic: a SARS-CoV-2 serosurvey of blood donors in New Zealand. (30th July 2021)

• Record Type: Journal Article
• Authors: Carlton, Lauren H.; Chen, Tiffany; Whitcombe, Alana L.; McGregor, Reuben; Scheurich, Greg; Sheen, Campbell R.; Dickson, James M.; Bullen, Chris; Chiang, Annie; Exeter, Daniel J.; Paynter, Janine; Baker, Michael G.; Charlewood, Richard; Moreland, Nicole J.
• Is Part Of: Epidemiology and infection. Volume 149(2021)
• Publication Date: 2021-07-30
• Subjects: COVID-19 -- elimination -- New Zealand -- receptor binding domain -- SARS-CoV-2 -- seroprevalence -- serosurvey -- Spike; Communicable diseases -- Periodicals; Epidemiology -- Periodicals; 614.4
• DOI: 10.1017/S0950268821001643
• Languages: English
• ISSNs: 0950-2688

Abstract

Abstract: New Zealand has a strategy of eliminating SARS-CoV-2 that has resulted in a low incidence of reported coronavirus-19 disease (COVID-19). The aim of this study was to describe the spread of SARS-CoV-2 in New Zealand via a nationwide serosurvey of blood donors. Samples ( n = 9806) were collected over a month-long period (3 December 2020–6 January 2021) from donors aged 16–88 years. The sample population was geographically spread, covering 16 of 20 district health board regions. A series of Spike-based immunoassays were utilised, and the serological testing algorithm was optimised for specificity given New Zealand is a low prevalence setting. Eighteen samples were seropositive for SARS-CoV-2 antibodies, six of which were retrospectively matched to previously confirmed COVID-19 cases. A further four were from donors that travelled to settings with a high risk of SARS-CoV-2 exposure, suggesting likely infection outside New Zealand. The remaining eight seropositive samples were from seven different district health regions for a true seroprevalence estimate, adjusted for test sensitivity and specificity, of 0.103% (95% confidence interval, 0.09–0.12%). The very low seroprevalence is consistent with limited undetected community transmission and provides robust, serological evidence to support New Zealand's successful elimination strategy for COVID-19.